President Donald Trump's repeated promises to end the Obama-era Iran nuclear deal may accomplish what Tehran has been trying to do for decades — drive a damaging wedge between the U.S. and key European allies, NBC News reported.

Trump has made no secret of his dislike for the 2015 agreement, which had painful sanctions lifted in exchange for Iran curbing its nuclear program. On the campaign trail, he called it "the worst deal ever."

On Thursday, Secretary of State Rex Tillerson said "Iran is clearly in default" of U.S. expectations for the pact. He cited Iranian support for Syrian President Bashar al-Assad, its development of ballistic missiles and "cyber activities."

While the Trump administration also extended sanctions relief to Tehran under that deal, NBC News reported that Trump plans to sign off on a new Iran policy ahead of his first appearance at the United Nations General Assembly next week. Trump is seeking to take a more aggressive approach, according to administration officials.